Got a business idea (or 10) in your back pocket? Meet six women who turned theirs into big bucks.

Melissa George

Melissa George

The idea: An instant fix for wayward hems

The story: "I was walking down Madison Avenue in my Balenciaga dress pants and wanted to change into flats to go into the subway," remembers George, who also happens to be the star of the Cinemax action-drama Hunted. "But I couldn’t, because of six inches of hem." That moment, the 36-year-old says, was the impetus for creating HemmingMyWay, her adhesive-snap invention that instantly shortens garments without tailoring. In 2009, the product launched online and then found a lucrative home on QVC (a 48-piece set costs $23); shortly thereafter, George and her business partner, Kara Harshbarger, unveiled an offshoot version, Style Snaps (16 pieces for $9.99), which made more than $15 million last year alone. Now, with four more patents in development, including a tablecloth adjuster, George continues to thrive as a curious Hollywood hybrid. "A casting agent came up to me and said, 'I heard a rumor that you invented that thing….' I said, 'Yes, but I'm an actress first and foremost, so please give me that movie!' People are either blown away by it or confused."

Danielle Fong

Danielle Fong

The idea: A system that uses giant tanks of compressed air to store energy

The story: There's the fast track—and then there's Fong, the cofounder of and chief scientist at Berkeley, California–based LightSail Energy. After graduating from college at 17, she left Princeton’s physics PhD program to start the company, which develops technology to make clean power from wind and solar farms available whenever it’s needed—not just when the weather permits—via highly effective storage tanks. Fong, 25, has said that the market for her innovative method (using compressed-air tanks and water to store and release power) is expected to exceed $1 trillion over the next 20 years. And with billionaire investors such as Bill Gates and PayPal cofounder Peter Thiel onboard, Fong is already seeing some serious green: LightSail Energy has raised more than $52 million since its founding in 2009.